Machine Tools for High Performance Machining

L.N. Lopez de Lacalle A. Lamikiz Editors Machine Tools for High Performance Machining Springer

Content Contributors xix 1 Machine Tools for Removal Processes: A General View 1 L. Norberto Lopez de Lacalle and A. Lamikiz 1.1 Basic Definitions and History 1 1.1.1 Historical Remarks 2 1.2 The Functions and Requirements of a Machine Tool 8 1.2.1 User and Technological Requirements 9 1.3 The Basic Mechanism 13 1.4 The Machine Structure 16 1.4.1 Machine Foundations 18 1.4.2 Structural Components Materials 18 1.4.3 Structural Analysis 19 1.4.4 Modularity 22 1.5 Guideways 23 1.5.1 Guides with Limit Lubrication 25 1.5.2 Rolling Guides 25 1.5.3 Hydrostatic Guides 26 1.6 The Definition of the Main Motion 27 1.7 The Definition of the Drive Trains 29 1.8 The CNC Implementation 30 1.9 Machine Verification 33 1.10 Typical Machines for Several Applications and Sectors 34 1.10.1 A Machine for Big Structural Turbine Parts 34 1.10.2 A Horizontal Milling Centre for Automotive Components 35 1.10.3 A Milling Centre for Moulds 37 1.10.4 A Milling Machine for Big Dies and Moulds 37 1.10.5 Conventional Machines for Auxiliary Operations 38 1.10.6 CNC Milling Machines for General Production 40 xi

xii Content 1.10.7 A Heavy-duty Lathe 40 1.10.8 A Mitre Band Saw 41 1.10.9 Transfer Machines 42 1.10.10 A Milling and Boring Centre 43 1.11 The Book Organisation 43 References 44 2 New Concepts for Structural Components 47 J. Zulaika andf. J. Campa 2.1 Introduction and Definitions 47 2.2 Optimised Machine Structures 49 2.2.1 A Comparison Among Different Machine Configurations 50 2.2.2 Structural Components in Machine Structures 53 2.2.3 Robust Rams and Columns 54 2.3 Structural Optimisation in Machines 56 2.3.1 Mechanical Requirements for Eco-efficient Machines... 56 2.3.2 FEM Modelling 58 2.3.3 Topological Optimisation 60 2.4 Structural Materials 61 2.4.1 Involved Parameters 61 2.4.2 Conventional Materials for Structural Components 62 2.4.3 Innovative Materials for Structural Components 63 2.4.4 Costs of Design Materials and Structures 65 2.4.5 The Influence of Innovative Materials on Productivity... 65 2.5 Active Damping Devices 66 2.5.1 The Implementation of ADDs to Machine Structures 67 2.6 The Influence of New Structural Concepts on Productivity 68 2.6.1 The Influence of New Design Concepts for Structural Components 68 2.6.2 The Influence of ADDs on Productivity 71 2.7 Future Trends in Structural Components for Machines 72 References 72 3 Machine Tool Spindles 75 G. Quintana, J. de Ciurana andf. J. Campa 3.1 Introduction 75 3.2 Types of Spindles 78 3.2.1 Belt-driven Spindles 78 3.2.2 Gear-driven Spindles 79 3.2.3 Direct Drive Spindles 79 3.2.4 Integrated (Built-in) Drive Spindles 80 3.3 Spindle Configurations 80 3.3.1 Common Configurations: Vertical and Horizontal Spindles 81

Content xiii 3.3.2 Machines with Rotary Headstocks 81 3.3.3 A Main Spindle with an Auxiliary Spindle 82 3.3.4 Twin Spindles and Multi-spindles 83 3.3.5 Automatic Head Exchange 83 3.4 Basic Elements of the Spindle 84 3.4.1 Motors 85 3.4.2 Bearings 87 3.4.3 The Toolholder 95 3.4.4 The Drawbar 102 3.4.5 The Shaft 103 3.4.6 The Sensors 103 3.4.7 The Housing 104 3.5 Spindle Properties and Performance 105 3.5.1 Spindle Power and Torque versus Spindle Speed Curves 105 3.5.2 The Stiffness 106 3.5.3 Dynamic Behaviour and Vibrations 108 3.5.4 The Thermal Behaviour 115 3.5.5 Spindles in Use: Other Problems 119 3.6 Spindle Selection 120 3.6.1 Conventional Machining or HSM 121 3.6.2 Tool Selection 122 3.6.3 The Workpiece Material 123 3.6.4 Power and Spindle Speed Requirements 123 3.7 Brief Conclusions 125 References 126 4 New Developments in Drives and Tables 129 A. Olarra, I. Ruiz de Argandona and L. Uriarte 4.1 Introduction 129 4.1.1 Precision and Dynamics 130 4.2 Linear Drives by Ball Screws 132 4.2.1 Dimensioning 132 4.2.2 The Rotary Screw 138 4.2.3 Other Configurations 138 4.3 Linear Drives by Rack and Pinion 139 4.3.1 The Elimination of the Gap 139 4.3.2 Dimensioning 141 4.3.3 Dynamic Models of the Drives 142 4.4 Linear Drives by Linear Motors 142 4.4.1 Mounting 144 4.4.2 Configurations 144 4.5 Rotary Drives 145 4.5.1 Mechanical Transmissions 145 4.5.2 Direct Rotary Drives 146

xiv Content 4.6 Guidance Systems 147 4.6.1 Friction Guides 147 4.6.2 Rolling Guides 150 4.6.3 Hydrostatic Guides 152 4.6.4 Aerostatic Guides 156 4.7 The Present and the Future 157 4.7.1 Rolling Guides with Integrated Functions 157 4.7.2 The Hydrostatic Shoe on Guide Rails 157 4.7.3 Guiding and Actuation through Magnetic Levitation 158 References 158 5 Advanced Controls for New Machining Processes 159 J. Ramon Alique andr. Haber 5.1 Introduction and History 159 5.1.1 Computer Numerical Control and Direct Numerical Control 160 5.1.2 Networked Control and Supervision 163 5.2 New Machining Processes 164 5.2.1 High Speed Machining 165 5.2.2 Micromechanical Machining 166 5.2.3 An Introduction to Nanomachining Processes 167 5.3 Today's CNCs: Machine Level Control 168 5.3.1 The Interpolation Process 169 5.3.2 The Position Control Servomechanism 174 5.4 Advanced CNCs: Multi-level Hierarchical Control 179 5.4.1 The Control of the Machining Process 181 5.4.2 The Supervisory Control of the Machining Process: Merit Variables 183 5.5 The Sensory System for Machining Processes 185 5.5.1 Correct Monitoring Conditions 188 5.5.2 Machining Characteristics and their Measurement 189 5.5.3 Two Case Studies 190 5.6 Open-Architecture CNC Systems 194 5.6.1 Networked Control and Supervision 195 5.7 Programming Support Systems: Manual Programming 202 5.7.1 Computer Assisted Programming 207 5.7.2 Graphical Simulation 209 5.8 Current CNC Architectures 210 5.8.1 Systems Based on Multi-microprocessor Architecture... 211 5.8.2 The PC Front-end 211 5.8.3 The Motion Control Card with a PC 212 5.8.4 The Software-based Solution 212 5.8.5 Fully Digital Architectures: Towards the Intelligent Machine Tool 214 References 216

Content xv 6 Machine Tool Performance and Precision 219 A. Lamikiz, L. N. Lopez de Lacalle and A. Celaya 6.1 Introduction and Definitions 220 6.1.1 An Introduction to Precision Machining 220 6.1.2 Basic Definitions: Accuracy, Repeatability and Resolution 223 6.1.3 Historical Remarks and the State of the Art 224 6.2 Basic Design Principles and an Error Budget 225 6.2.1 Sources of Errors in Machine Tools 226 6.2.2 Error Budget Estimation 227 6.2.3 Basic Principles for Precision Machine Design 231 6.2.4 Error Propagation 237 6.2.5 Thermal Errors 240 6.2.6 CNC Interpolation Errors 244 6.3 Errors Originated by the Machining Process 245 6.3.1 Errors Originated in the CNC Program Generation 245 6.3.2 Errors Originated by the Tool Wear 247 6.3.3 Tool Deflection Error 248 6.4 Verification Procedures 251 6.4.1 Standard Procedures for Machine Tool Validation 252 6.4.2 Test Parts 257 6.5 A Brief Conclusion 258 References 259 7 New Developments in Lathes and Turning Centres 261 R. Lizarralde, A. Azkarate and O. Zelaieta 7.1 Introduction 261 7.2 Machine Configuration 262 7.2.1 High Production Lathes 262 7.2.2 Turning Centres: Multi-tasking Machines 265 7.3 The Latest Technologies Applied to Lathes and Turning Centres 270 7.3.1 General Configuration Technologies 270 7.3.2 Complementary Technologies to Improve Machine Performance 271 7.4 Special Machining Processes Applied in Multi-tasking Machines 272 7.4.1 The Laser Application 272 7.4.2 Roller Burnishing and Deep Rolling 273 7.4.3 Ultrasonic Assisted Turning 275 7.4.4 Cryogenic Gas Assisted Turning 276 7.4.5 High-pressure Coolant Assisted Machining 277 References 278

xvi Content 8 High Performance Grinding Machines 279 R. Lizarralde, J. A. Maranön, A. Mendikute and H. Urreta 8.1 Introduction 279 8.2 The Machine Configuration 280 8.2.1 The Machine Architecture 281 8.2.2 Materials Applied in Structural Parts 286 8.2.3 Main Components 288 8.2.4 Wheel Dressing Systems 291 8.2.5 Process Lubrication and Cooling 296 8.2.6 Integrated Measuring Devices 297 8.3 Special Grinding Processes 299 8.3.1 Peel Grinding-Quick Point 299 8.3.2 Speed Stroke Grinding 300 8.3.3 Creep Feed Grinding 301 8.3.4 High Efficiency Deep Grinding 302 8.4 Machine and Process Monitoring and Control 302 8.4.1 Monitored Parameters and Applied Sensors 303 8.4.2 Control Strategies 304 References 305 9 Wire Electrical Discharge Machines 307 J. A. Sanchez and N. Ortega 9.1 Introduction 307 9.2 The WEDM Process 310 9.2.1 Accuracy and Speed 312 9.3 WEDM Machines 315 9.3.1 Wire Transport and Wire Thread Devices 318 9.3.2 Machine Automation 319 9.3.3 Workpiece Fixturing Systems 321 9.3.4 Filtering Systems 322 9.4 Wires for WEDM 323 9.5 The Wire EDM of Advanced Materials 326 9.5.1 Aeronautical Alloys 326 9.5.2 Tungsten Carbide 327 9.5.3 Advanced Ceramics and PCD 328 9.6 Thin-wire EDM 330 References 332 10 Parallel Kinematics for Machine Tools 335 O. Altuzarra, A. Hernandez, Y. San Martin and J. Larranaga 10.1 Introduction 335 10.2 Main Characteristics of the Parallel Kinematic Machines 337 10.3 A Classification of the Parallel Kinematic Machines 338 10.4 A Design Methodology for Parallel Kinematic Machines 339 10.4.1 The Motion Pattern 340

Content xvii 10.4.2 The Type Synthesis 341 10.4.3 The Position Analysis 345 10.4.4 Velocity Analysis, Singularities and Dynamics 347 10.4.5 The Optimisation 349 10.5 The Kinematic Calibration of PKMs 349 10.5.1 A Mathematical Approach 351 10.5.2 Measuring on External Methods 353 10.5.3 Self-calibration Strategies 358 10.6 The Control of Parallel Kinematic Machines 358 10.6.1 Models Specific to Parallel Kinematics Machines 360 10.6.2 The Dynamic Controller 361 10.6.3 The Model-based Predictive Controller 363 10.7 Conclusions and Future Trends 365 References 366 11 Micromilling Machines 369 L. Uriarte, J. Eguia andf. Egana 11.1 Introduction and Definitions 369 11.2 The Micromilling Process 371 11.2.1 Micromilling Tools 372 11.2.2 Applications 374 11.3 Miniaturised Machine Tools 376 11.4 Machine Drives 377 11.4.1 Conventional Ball Screw Configuration 377 11.4.2 Friction Drives 379 11.4.3 The Linear Motor 380 11.4.4 New Tendencies: Hydrostatic Screws 382 11.5 Guideways 383 11.5.1 Special Rolling Guides Configurations 383 11.5.2 Aerostatic and Hydrostatic Guides 384 11.5.3 New Tendencies: Magnetic and Flexure Guidance Systems 386 11.6 The High Speed Spindle and Collet 389 11.6.1 Alternatives: Hydrostatic and Magnetic Spindles 390 11.7 Measuring Systems 392 11.8 Examples 393 11.8.1 The Kern Pyramid Nano 393 11.8.2 The Kugler Microgantry nano 3/5X 395 References 396 12 Machines for the Aeronautical Industry 399 J. Fernandez and M. Arizmendi 12.1 Aeronautical Business 399 12.2 Aerospace Components 400 12.2.1 Aerospace Structures 401

xvüi Content 12.2.2 Aerospace Engines 402 12.2.3 Accessories 403 12.3 Aerospace Materials 403 12.4 Costs, Weight and Precision in Machine Tools for Aerospace Machining 405 12.4.1 The Drive to Reduce Aircraft Costs 406 12.4.2 The Drive to Reduce Aircraft Weight 407 12.4.3 The Drive for Aircraft Component Precision 407 12.5 Machine Tools for Aeronautical Components 408 12.5.1 Machine Tools for Machining Aeronautical Structures... 409 12.5.2 Machine Tools for Machining Engine Components 413 12.5.3 Machine Tools for Machining Accessories and Structure Fittings 417 References 419 13 Machine Tools for the Automotive Industry 421 Ciro A. Rodriguez and Horacio Ahuett 13.1 World Trends in Automotive Production 421 13.1.1 The Economic Impact of the Automotive Industry 421 13.1.2 Machining Processes in Automotive Production 422 13.2 Manufacturing System Architecture: High Volume Production Versus Flexibility 423 13.2.1 Dedicated Machines 424 13.2.2 Flexible Cells 427 13.2.3 Hybrid Systems 429 13.3 Technology Trends 433 References 435 Index 437